1. Field of the Invention
The present invention relates to a voice recognition system, a communication terminal, a voice recognition server and a computer program, more particularly to sending a voice signal from the communication terminal to the voice recognition server and to recognizing the voice signal from the communication terminal received by the voice recognition server.
2. Description of Related Art
A voice recognition system has a communication terminal and a voice recognition server. The communication terminal sends an inputted voice signal to the voice recognition server. The voice recognition server recognizes the voice signal from the communication terminal. The communication terminal may be installed in a vehicle. In this case, the voice signal is inputted to the communication terminal and sent to the voice recognition server via a communication network. For example, if a user inputs words “route search” to the vehicle unit, the vehicle unit sends the voice signal to the voice recognition server via a communication network. When the voice recognition server receives the voice signal from the vehicle unit, the voice recognition server recognizes the received voice signal. Then the voice recognition server searches a route between a present position and a destination based on the recognized voice signal, and sends the search result to the vehicle unit via the communication network. When the vehicle unit receives the search result, the vehicle unit shows the route information on a display. Therefore, the user is provided with information of the route between the present position and the destination just by uttering the words “route search”.
In such a voice recognition system, a sound characteristic of a communication network between the vehicle unit and the voice recognition server requires to be adjusted so that the voice recognition server recognizes properly the voice signal. The sound characteristic is generally adjusted by the voice recognition server.
However, adjusting the sound characteristic by the voice recognition server requires a large database. That is because the voice recognition server communicates with multiple vehicle units or other communication devices, such as personal digital assistant terminals (PDA). Moreover, if such a database is not provided, the voice recognition server does not properly recognize the voice signal, and cannot get a desired performance for voice recognition.